Armed rebels forced the emergency workers to hand over the remains, the Associated Press reported, citing Ukrainian officials and monitors. Journalists saw no rebels and no bodies at the crash site Sunday morning. Emergency workers remained on the scene, searching the field for body parts.

On Saturday, international outrage over treatment of the bodies — many still strapped to their seats, decomposing in vast fields around the crash site — grew to a fever pitch.

Nataliya Khuruzhaya, a duty officer at the train station in Torez, 9 miles from the crash site, told the AP she saw emergency workers loading plane victims’ bodies Sunday morning into five sealed, refrigerated train cars.

She said the train was scheduled to go to Ilovaysk, closer to the Russian border.

Russian news reports have said the bodies were being taken to Donetsk, a rebel-held stronghold.

Ukrainian Emergency Ministry spokeswoman Nataliya Bystro said recovery workers in the rebel-held territory were forced to give the bodies to the armed gunmen and didn’t know where they were going, the AP reported.

The Malaysian airliner — en route from Amsterdam to Kuala Lumpur with 283 passengers and 15 crew members — crashed Thursday after being hit by what U.S. officials say was an SA-11 surface-to-air missile. There were no survivors. Dozens of bodies remain unaccounted for.

The latest U.S. intelligence assessment suggests that more than one missile system was provided to the separatists by the Russians in the last week or so, a U.S. official said Saturday, according to reports by the Associated Press and The Wall Street Journal.

While there is not 100 percent certainty, the official told AP, “more and more there is the general belief that the systems were provided by the Russians.”

The official said it’s not entirely clear if the separatists just received the missile systems or if they had them for a short time and only in recent days were trained or able to operate them. The official was not authorized to discuss the matter publicly and spoke on condition of anonymity.

Also Sunday, British Prime Minister David Cameron minced no words in an article for the Sunday Times, calling the attack a “direct result of Russia destabilizing a sovereign state.”

In a related development, U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov agreed by phone Saturday that all evidence in the case be turned over to independent, international investigators, the ITAR-TASS news agency reports.

“During the frank discussion, the minister and the secretary, without mincing words, exchanged assessments and arguments and agreed on the main point that it is necessary to ensure an absolutely impartial, independent and open international investigation of the Malaysian plane crash,” the Russian Foreign Ministry said in a statement.

The International Civil Aviation Organization should play a leading role in the investigation, the statement said.

Lavrov and Kerry agreed that “all evidence, including flight data recorders, should be made available for examination as part of an international investigation and that all necessary conditions should be created on the ground to ensure access for the international team of experts.”

Dutch Foreign Minister Frans Timmermans, at a Saturday meeting with Ukrainian President Petro Poroshenko, said he was “shocked by the news we got today of bodies being dragged around, of the site not being treated properly,” Reuters reported.

“People are angry, furious,” he said, telling Poroshenko that the Netherlands wanted to know who was responsible for shooting down the airliner.

“Once we have the proof, we will not stop before the people are brought to justice,” the minister said, according to Reuters. “Not just the people who pulled the trigger but also those who made it possible. I think the international community needs to step up its efforts in this respect.”

Most of the people who died in the aircraft, which took off from the Netherlands’ Schiphol airport, were Dutch.

Groisman said 192 bodies have been recovered from the crash site so far.

Malaysia Minister of Transport Liow Tiong Lai said his country was “deeply concerned” about whether the crash site is being properly secured.

“The integrity of the site has been compromised and there are indications that vital evidence has not been preserved in place,” he said.

On a dirt road near the site Saturday morning, separatist officials from the self-proclaimed Donetsk People’s Republic’s ministry of internal affairs began moving bodies in what appeared to be an unorganized and ad hoc operation.

At one point, about 15 bodies had been laid out on the rural road.

“Experts are removing the bodies,” a separatist soldier who identified himself as Commander Ugriumny and seemed to be in charge told reporters. “Where we will move them, we will wait and see.”

Until the soldiers arrived in a 10-vehicle caravan, the golden fields in this remote region near the Russian border were virtually empty, except for the decomposing bodies, some still strapped to their airline seats, and wide swaths of plane wreckage. There were no emergency services vehicles, no separatist soldiers.

The militiamen, who began setting up a perimeter, cordoning off the area and putting up tents, scoffed at charges by the Kiev government that bodies were being removed from the scene.

“No one stole any bodies,” said Commander Ugriumny. “Or have taken them anywhere.”

Russian journalist Ilya Vasyunin also tweeted photos of what he said were teams from Ukraine’s emergency service loading bodies of victims onto a truck.

An international delegation visited the crash site Friday evening but was only allowed a superficial visit to see one small portion.

Among the passengers from 11 countries were 80 children, an acclaimed AIDS researcher from Amsterdam, a nun, a teacher from Sydney, a Dutch senator, a Malaysian actress and a World Health Organization spokesman.

One American with dual Dutch citizenship was also among the dead.

Ukraine has accused Russia of helping rebels destroy evidence at the crash site. Russia, while separatist groups have denied being responsible for the shootdown.

Vitaly Nayda, head of counterintelligence for the Ukrainian Security Service, presented photographs on Saturday that he said depicted three of the Buk missile systems — like one believed to have been used in the shootdown — on the road to the Russian border. Two of the mobile systems crossed the border into Russia at about 2 a.m. Friday, he said, less than 10 hours after the shootdown.

He said a third Buk system crossed into Russia around 4 a.m.

“We have proof that the terrorist attack was planned and carried out with the involvement of representatives of the Russian Federation,” Nayda said. “We know that Russia is trying to hide its terrorist activity and their direct involvement.”

On Friday, the SBU posted a video of what it said was one of the mobile systems moving out of the area with at least one of its four missiles missing.

Ukraine earlier echoed demands that President Obama made on Friday that investigators be granted access to the wreckage.